Collecting activity information to evaluate therapy

Abstract

A medical device delivers a therapy to a patient. The medical device or another device may periodically determine an activity level of the patient, and associate each determined activity level with a current therapy parameter set. A value of at least one activity metric is determined for each of a plurality of therapy parameter sets based on the activity levels associated with that therapy parameter set. A list of the therapy parameter sets is presented to a user, such as a clinician, for evaluation of the relative efficacy of the therapy parameter sets. The list may be ordered according to the one or more activity metric values to aid in evaluation of the therapy parameter sets. Where values are determined for a plurality of activity metrics, the list may be ordered according to the one of the activity metrics selected by the user.

1. A method comprising:
 monitoring a signal that varies as a function of patient activity; 
 periodically determining an activity level of the patient based on the signal; 
 associating each of the determined activity levels with a therapy parameter set currently used by a medical device to deliver a therapy to a the patient when the activity level is was determined, wherein the therapy comprises at least one of a movement disorder therapy, psychological disorder therapy, or deep brain stimulation; and 
 determining a value of an activity metric for each of a plurality of therapy parameter sets based on activity levels associated with the therapy parameter sets. 
 
   
   
     2. The method of  claim 1 , wherein determining a value of an activity metric comprises determining at least one of a mean and a median of activity levels associated with the therapy parameter set. 
   
   
     3. The method of  claim 2 , wherein determining a value of an activity metric comprises:
 comparing the at least one of the mean and the median activity level to at least one threshold; and 
 selecting the activity metric value from a plurality of predetermined possible activity metric values based on the comparison. 
 
   
   
     4. The method of  claim 1 , wherein determining a value of an activity metric for a therapy parameter set comprises:
 comparing each of the activity levels associated with the therapy parameter set to a threshold value; and 
 determining at least one of a percentage of time above the threshold and a percentage of time below the threshold. 
 
   
   
     5. The method of  claim 1 , wherein determining a value of an activity metric for a therapy parameter set comprises:
 comparing each of the activity levels associated with the therapy parameter set to a threshold value; and 
 determining an average length of time that consecutively determined activity levels associated with the therapy parameter set were above the threshold. 
 
   
   
     6. The method of  claim 1 , wherein determining an activity metric value for each of a plurality of therapy parameter sets comprises determining an average number of activity counts per a unit of time for each of the plurality of therapy parameter sets based on a number of activity counts associated with each of the therapy parameter sets. 
   
   
     7. The method of  claim 1 , further comprising presenting a list of the plurality of therapy parameter sets and activity metric values associated with the therapy parameter sets. 
   
   
     8. The method of  claim 7 , further comprising ordering the list of therapy parameter sets according to the associated activity metric values. 
   
   
     9. The method of  claim 8 , wherein determining a value of an activity metric comprises determining a value of each of a plurality of activity metrics for each of a plurality of therapy parameter sets based on activity levels associated with the therapy parameter sets, and ordering the list comprises ordering the list according to a user selected one of the activity metrics. 
   
   
     10. A medical system comprising:
 a medical device that delivers at least one of a movement disorder therapy, psychological disorder therapy, or deep brain stimulation to a patient; and 
 a processor that monitors a signal that varies as a function of patient activity, periodically determines an activity level of the patient based on the signal, associates each of the determined activity levels with a therapy parameter set used by the medical device to deliver the at least one of the movement disorder therapy, psychological disorder therapy, or deep brain stimulation to the patient when the activity level was determined, and determines a value of an activity metric for each of a plurality of therapy parameter sets based on activity levels associated with the therapy parameter sets. 
 
   
   
     11. The medical system of  claim 10 , wherein, for each of the therapy parameter sets, the processor determines at least one of a mean and a median of activity levels associated with the therapy parameter set. 
   
   
     12. The medical system of  claim 11 , wherein, for each of the therapy parameter sets, the processor compares the at least one of the mean and the median activity level to at least one threshold, and selects an activity metric value from a plurality of predetermined possible activity metric values based on the comparison. 
   
   
     13. The medical system of  claim 10 , wherein, for each of the therapy parameter sets, the processor compares each of the activity levels associated with the therapy parameter set to a threshold value, and determines as the activity metric value for the therapy parameter set at least one of a percentage of time above the threshold and a percentage of time below the threshold. 
   
   
     14. The medical system of  claim 10 , wherein, for each of the plurality of parameter sets, the processor compares each of the activity levels associated with the therapy parameter set to a threshold value, and determines as the activity metric value for the parameter set an average length of time that consecutively determined activity levels were above the threshold. 
   
   
     15. The medical system of  claim 10 , wherein an activity level comprises a number of activity counts, and the activity metric value for each of the therapy parameter sets comprises an average number of activity counts per a unit of time. 
   
   
     16. The medical system of  claim 10 , further comprising a programming device that includes a display to present a list of the plurality of therapy parameter sets and activity metric values associated with the therapy parameter sets. 
   
   
     17. The medical system of  claim 16 , wherein the programming device orders the list of therapy parameter sets according to the associated activity metric values. 
   
   
     18. The medical system of  claim 17 , wherein the processor determines a value of each of a plurality of activity metrics for each of the plurality of therapy parameter sets based on activity levels associated with the therapy parameter sets, and the programming device orders the list according to a user selected one of the activity metrics. 
   
   
     19. The medical system of  claim 10 , wherein the medical device comprises an implantable medical device. 
   
   
     20. The medical system of  claim 10 , wherein the medical device comprises at least one of an implantable neurostimulator or an implantable pump. 
   
   
     21. A medical system comprising:
 means for delivering at least one of a movement disorder therapy, psychological disorder therapy, or deep brain stimulation to a patient; 
 means for monitoring a signal that varies as a function of patient activity; 
 means for periodically determining an activity level of the patient based on the signal; 
 means for associating each of the determined activity levels with a therapy parameter set used by the means for delivering to deliver the at least one of the movement disorder therapy, psychological disorder therapy, or deep brain stimulation to the patient when the activity level was determined; and 
 means for determining a value of an activity metric for each of a plurality of therapy parameter sets based on activity levels associated with the therapy parameter sets.